Drones need antennas to respond to instructions given by the person holding the controller. A technical hurdle you may meet when deciding on your FPV video feed setup is the type of antennae to use. There are two types of antennas, RHCP, and the LHCP. Don’t be overwhelmed, it’s easy, we’ve outlined the basics below.
RHCP antennas are known in full as Right Hand Circular Polarized antennas. LHCP antennas are known in full as Left Hand Circular Polarized antennas. Sometimes, they are both known simply as Circular Polarized (CP) antennas. Due to its polarized nature, this type of antenna will reduce any radio interference by a process known as multipathing. This blocks out unwanted radio signals and can give a much cleaner signal.
The main difference between RHCP and LHCP is the difference in the sides of polarization. The RHCP makes use of right-hand side polarization while the LHCP makes use of polarization on the left side. Usually, when you are purchasing this gear, it will come as a pair for both receiver and transmitter. If you are ordering a replacement or customizing your equipment, the basic rule is below.
Make sure you use the same type of receiver and transmitter.
Both types are as good as the other. However, it is essential to use one type at a time and avoid mixing them together. If you don’t match the range will not be as good, and you will have a lot of interference, in fact, the range will be reduced to up to -30db that’s about 1000 times weaker than a matching antenna.
Choose the least popular
The polarization of the antennas is interleaved on channels that are next to each other. This is the benefit of Circular Polarization (CP), and this allows for more radio channels in the same frequency without interference.
If you and all your friends use LHCP it can still cause interference, if multiple flyers are in the same area, you can further reduce interference by ensuring there is a combination left and right antenna setups in use. If all your friends use LHCP and you use RHCP, you will have a much cleaner signal, so it is better to be using the least popular antennae type.
Remember to always field test when entering a new flying area as each location will have different signal ranges, and always be sure to inform anyone in the area of your FPV adventures. I hope this has helped you learn the difference between RH and LH Circular Polarization antennae, we have some DIY CP antennae available and be sure to ask any questions, and our team can help you.